Factory safety - Safety in manufacturing – a holistic approach


Two new white papers from Rockwell Automation reveal how progressive manufacturers are focusing on safety automation solutions to keep their people safe, their machines working and their bottom lines robust. The papers credit this focus to the adoption of a ‘holistic approach to safety' and ‘Providing the value of safety', which emphasise global standards, innovative technologies, trained personnel and ongoing risk assessment, all working together

"A Holistic Approach to Safety Automation" highlights the differences between the manufacturing industry's historical approach of separating safety solutions from the automation system, and today's integrated functional approach to safety. It also outlines the inherent benefits this direction offers, namely minimised risk and increased productivity.

"By integrating safety functions into their overall automation strategy platform, manufacturers can create a safer working environment for employees and reduce the risk of an incident that could have a negative environmental impact. It also improves manufacturing processes that optimise productivity and key performance indicators, such as overall equipment effectiveness, ultimately leading to increased profits," said Craig Resnick, research director, ARC Advisory Group. "When manufacturers adopt this holistic approach to safety, they are leveraging state-of-the-art technology to help protect their people, as well as improving their company's global competitiveness."
A fundamental shift in two essential and related areas has helped make this new functional approach to safety possible. The first is major developments in safeguarding and control technologies - most notably the advent of new microprocessor-based technologies in lieu of electromechanical or hard-wired control. The second is the evolution of global safety standards to allow these new electronic technologies to be incorporated into industrial safety systems.
The increased popularity of proactive risk analysis is also helping to propel the growth of this holistic approach, according to the paper. The objective of the safety system is to help protect people by making processes and machines safer without decreasing productivity. Manufacturers that conduct risk assessments are several steps closer to achieving all of the above - and in so doing, they help reduce risk and the costs associated with it.
"The holistic approach to safety is a best practice that ARC hopes even more manufacturers adopt," Resnick said. "Manufacturers should challenge their automation suppliers to provide innovative safety solutions and services to support their quests to operate safer, while simultaneously increasing productivity and profitability. Rockwell Automation appears to have met this challenge with their integrated safety solution offerings."
‘Providing the value of safety' outlines the long-term financial benefits manufacturers can reap by integrating comprehensive machine safety programmes into their workplaces as a form of insurance against potential risks.
 Functional safety protects workers by reducing incidents but also reduces the associated costs. These include insurance premiums, claims administration fees, workers' compensation claims, risk management department costs (salary, travel, fringe benefits, and so on), legal fees, and other related costs such as government fees, assessments and consultants.
It benefits users by cutting costs without reducing safety. It provides a high safety/failure ratio so that users can maximise both production and safety. 

Functional safety is the part of the overall safety implementation that depends on the correct functioning of the process or equipment in response to operational safety inputs. It relates to the physical operation of a machine or process. In other words, functional safety equals the confidence in the ability of the safety-related control system to perform its function over a specified time period.

The name ‘functional safety' is often associated only with programmable safety systems, but this is a misconception. It covers a range of devices, such as interlocks, light curtains, safety relays, safety PLCs, safety contactors and safety drives that are interconnected to form a safety system.

Using functional safety and its applicable standards requires the availability of data such as the probability of dangerous failure per hour (PFHd) or mean time to dangerous failure (MTTFd). In this way, the user can calculate the reliability of the safety system. This should not be regarded as an absolute and certain value but more as an indicative and relative quantification that can prevent the use of unsuitable equipment.

Functional safety falls under the umbrella of the risk reduction process which involves the following steps: 
- Eliminate problems by design using inherently safe design concepts. 
- Safeguarding and protective measures with hard guarding and safety devices. 
- Complimentary safety measures including personal protective equipment (PPE). 
- Safe working practice achieved with procedures, training and supervision.
Functional safety addresses the safeguarding portion of the risk reduction process. When users implement integrated safety by designing systems so that safety and environmental considerations are fundamental elements, they include functional safety measures as part of the safety system.

When designing equipment and associated control systems, a hazard analysis will help determine whether functional safety is necessary to ensure adequate protection against each significant hazard. If so, then users can integrate functional safety into the machine design requirements, implementation and validation.

A hazard analysis identifies what has to be done to avoid hazardous events associated with the operation and maintenance of the machinery. In addition, a risk assessment gives the safety integrity required of the safety system for the risk to be acceptable. 
As safety becomes more and more important in today's world, it makes sense for systems to be fully integrated into the factory environment.  The fact that it provides other significant benefits along the way is a real bonus.

The white papers "A Holistic Approach to Safety" and "Providing the Value of Safety" are both available at: http://www.rockwellautomation.com/solutions/safety/